Televisión or televisor ?
The easiest way to learn the difference is to remember that "(el) televisor" refers to the TV set itself (the apparatus or machinery). With that out of the way, you can use the word "televisión" in pretty much all other situations. Here's a general usage definition:
"(El) televisor" is the TV set, whereas "(la) televisión" refers to the industry or programming.
Also, notice in example 4 that the verb "ver" (to see) is generally the verb used to mean "watch TV" and not the verb "mirar".
And here are some examples:
1. ¿Por qué pasas tanto tiempo delante del televisor? = Why do you spend so much time in front of the TV (set)?
2. No me gusta la televisión. = I don't like (to watch) TV.
3. ¿Hay algo en la televisión esta noche? = Is there anything on TV tonight?
4. El pasa el día viendo la televisión = He spends all day watching TV.
5. Tienen una oferta en televisores esta semana = They have a special offer on TV sets this week.
6. No olvides limpiar el televisor también = Don't forget to clean the TV set too.
Brad

